From dcac86b7d0be71563d6219ce52c9918e44b84f0a Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 3 Mar 2018 10:53:24 +0100 Subject: vga_switcheroo: Update PCI current_state on power change When cutting power to a GPU and its integrated HDA controller, their cached current_state should be updated to D3cold to reflect reality. We currently rely on the DRM and HDA drivers to do that, however: - The HDA driver updates the current_state in azx_vs_set_state(), which will no longer be called with driver power control once we migrate to device links. (It will still be called with manual power control.) - If the HDA device is not bound, its current_state remains at D0 even though the GPU driver may decide to go to D3cold. - The DRM drivers update the current_state using pci_set_power_state() which can't put the device into a deeper power state than D3hot if the GPU is not deemed power-manageable by the platform (even though it *is* power-manageable by some nonstandard means, such as a _DSM). Centralize updating the current_state of the GPU and HDA controller in vga_switcheroo's ->runtime_suspend hook to overcome these deficiencies. The GPU and HDA controller are two functions of the same PCI device (VGA class device on function 0 and audio device on function 1) and no other PCI devices reside on the same bus since this is a PCIe point-to-point link, so we can just walk the bus and update the current_state of all devices. On ->runtime_resume, the HDA controller is in D0uninitialized state. Resume to D0active and then let it autosuspend as it sees fit. Note that vga_switcheroo_init_domain_pm_ops() is not supposed to be called by hybrid graphics laptops which power down the GPU via its root port's _PR3 resources and consequently vga_switcheroo_runtime_suspend() is not used. On those laptops, the root port is power-manageable by the platform (instead of by a nonstandard means) and the current_state is therefore updated by the PCI core through the following call chain: pci_set_power_state() __pci_complete_power_transition() pci_bus_set_current_state() Resuming to D0active happens through: pci_set_power_state() __pci_start_power_transition() pci_wakeup_bus() Cc: Dave Airlie Cc: Ben Skeggs Cc: Takashi Iwai Cc: Alex Deucher Cc: Bjorn Helgaas Cc: Rafael J. Wysocki Reviewed-by: Peter Wu Tested-by: Kai Heng Feng # AMD PowerXpress Tested-by: Mike Lothian # AMD PowerXpress Tested-by: Denis Lisov # Nvidia Optimus Tested-by: Peter Wu # Nvidia Optimus Tested-by: Lukas Wunner # MacBook Pro Signed-off-by: Lukas Wunner Link: https://patchwork.freedesktop.org/patch/msgid/8416958482c8c42d6f311ea5c1e5a65ccf21f5db.1520068884.git.lukas@wunner.de --- drivers/gpu/vga/vga_switcheroo.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/gpu/vga') diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c index 3cd153c6d271..09dd40dd1dbe 100644 --- a/drivers/gpu/vga/vga_switcheroo.c +++ b/drivers/gpu/vga/vga_switcheroo.c @@ -1022,6 +1022,7 @@ static int vga_switcheroo_runtime_suspend(struct device *dev) vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD); mutex_unlock(&vgasr_priv.mux_hw_lock); } + pci_bus_set_current_state(pdev->bus, PCI_D3cold); vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF); mutex_unlock(&vgasr_mutex); return 0; @@ -1035,6 +1036,7 @@ static int vga_switcheroo_runtime_resume(struct device *dev) mutex_lock(&vgasr_mutex); vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_ON); mutex_unlock(&vgasr_mutex); + pci_wakeup_bus(pdev->bus); ret = dev->bus->pm->runtime_resume(dev); if (ret) return ret; -- cgit